AN UPDATED INVENTORY OF POTENTIAL PCDD AND PCDF EMISSION SOURCES IN THE UK

This study updates previous estimates of emissions to the UK atmospher e of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dib enzofurans (PCDFs). Following a systematic screening of a range of ind ustrial processes operating in the UK for the potential to release PCD D/Fs to atmosphere, 23 industrial processes were shortlisted for furth er consideration as potential emitters. To these processes were added six non-industrial sources of PCDD/F emissions; domestic coal and wood combustion, crematoria, traffic, natural fires and accidental fires. For each shortlisted process emission factors were identified. Emissio n factors were combined with the quantity of material treated or produ ced to generate an estimate of the annual quantity of PCDD/Fs released to atmosphere. The total estimated current emissions to atmosphere ra nged from 560 to 1100 g I-TEQ year(-1), with industrial processes cont ributing 535-955 g I-TEQ year(-1), an average of approximately 90% of the total inventory. Emissions from MSW incineration plants were domin ant, contributing an average of 70% to the total emissions from indust rial sources. Emissions from coal combustion, sinter plants, iron and steel plants, non-ferrous metals operations and incineration of clinic al waste collectively contributed an average of 25% to total industria l emissions in roughly equal proportions. The effect of tightening emi ssion controls was also examined. Assuming a situation when current re gulations concerning PCDD/F emissions are fully implemented, a reducti on in emissions from 560-1100 g I-TEQ year(-1) to 110-350 g I-TEQ year (-1) is envisaged. The largest reduction is effected through the impos ition of a 1 ng I-TEQ m(-3) emission limit on MSW and clinical waste i ncinerators: the contribution from these sources falls from the presen t range of 60-85% to approximately 6-18% of total emissions.